Process of roasting and sintering ores.



No. 882,518. PATENTED MAR. 17, 1908. A. S. DWIGHT & R. L. LLOYD.

PROCESS OF ROASTING AND SIN-TERING ORES.

.APPLIQATIONIILED JULY 30, 1906.

I 61mm,

UNITED STA'i ES PATENT OFFICE.

ARTHUR S. DWIGHT AND RICHARD L. LLOYD, OF CANANEA, MEXICO.

PROCESS OF BOASTING AND SINTERING- ORES.

Specification of Letters Patent.

Eatented March 17, 1908.

Application filed July-30, 1906. Serial No. 328,387.

To all whom it may concern:

Be it known that we, ARTHUR S. DWIGHT and RICHARD L. LLOYD, citizens of the United States, residing at Cananea, in the State of Sonora and Republic of Mexico, have invented certain new and useful Improvements in Processes of Roasting and Sintering Ores, of which the following is a specification, reference being had therein to the accompanying drawing.

Our invention relates to improvements in the processes for treating metal bearing substances, and especially to processes for treating sulfid and analogous ores, the improvements being particularly, though not exclusively, ap licable to the treatment of ores and metal urgical products when they are in a finely divided condition.

Among the objects aimed at are to effect a rapid and economical treatment of the ma-.

terials and to insure that after treatment they shall be in such physical condition that they maybe readily and cheaply manipulated during subsequent stages of reduction, and to these ends a further object of the invention is to make possible a continuous treatment of the materials as distinguished from those which are intermittent in their nature.

We have in another application, filed on the 22nd day of March, 1906, Serial No. 307 ,431', described old processes of roasting and sintering ores, and set out the difiiculties that have been met with in the treatment of ores or materials of the kind herein contemplated. We also therein pointed out the de-- sirability, in treating these fine ores by means of internal combustion carried on in sults attained in such devices are superior to those reached in the employment of any of the earlier kinds of apparatus of which we have knowledge, it has been found that many desirable results can not be obtained unless the material bemanipulated in the ways not possible by the use of such apparatus. One desideratum in the treatment of ore to sinter it is a rapid, complete and uniform firing or igniting of the mass, and this we have found can be most satisfactoril accomplished by moving the ore mass itsef bodily relative to an igniter, which may be stationary, in contradistinction from igniting by fire-starting means brought to or applied to a stationary mass, which last referred to means are irregular and intermittent in operation. And, again, when working according to the method described in the said application and when'employing apparatus such as shown therein, there was no provision made for maintaining continuity and uniformity in the action of the air supplying devices which, for each charge of material treated had to be started, kept in operation for a time and then stopped. It is, however, very desirable, and is one of the objects of the present invention, to have all parts of the ore-mass uniformly affected by a constant stream or supply of air; and this also can be attained by moving the ore-mass bodily relative to an air-inducing mechanism, as this avoids the necessity of raising or lowering the air-Suppl And again, it has been found desirab e to'treat the material in relatively thin masses so that the air can readily pass through it without requiring high air pressure, (this in turn necessitating greater ower and expense in operation than when ower pressures areemployed) and so that the resulting cake or biscuit of sinter being thin, ma be easily broken into pieces suitable for eing charged into a blast furnace. Theseadvantages can be secured by operating according to the present method of treatment inasmuch as the movirig of a mass of ore bodily permits it to be disposed of in a mass of uniform dimensions and so thin that the necessity of manual labor is reduced and a large quantity of material can be passed through the stages of treatment with economy in time, although it is subjected to air currents of low pressure and reduced power.

The present process contemplates-so arranging the ore in a mass or in a succession of masses that it can be moved from point to point during the stages of treatment, this permittin the combustible elements to be quickly, t oroughly, and uniformly lgmted; permitting the ore to be so arranged that line 33 of Fig. 1.

with the obvious advantages in economy incident thereto, and to the reducing of manual labor to a minimum; and permitting separation. of the locations for feedinga'nd discharging the material; thus making the handling of the crude ore and the sintered product more convenient. All of the features of operation just referred to can when 7 once adjusted be maintained uniformly and hence all the factors of success can be ke t at their maximum efficiency, Whereas int e intermittent processes these factors have to be adjusted for each separate charge of material treated. i

In the accompanying drawings We have illustrated a simple apparatus by means of which our improved process may be carried out. I Figure '1 is a longitudinal sectional view of the apparatus; Fig. 2 1s a perspective View of two sections of the carrier for the ore; and Fig. 3 isa cross sectional view taken on the In these drawings, A represents a guide for the carriers upon which the ore rests; while being roasted and sintered. It consists of a longitudinally and preferably horizontally arranged box-like structure con structed of suitable refractory material. One end, a, of the guide is preferably left open, this being the delivery end, and at a the other end there is arranged a feeding device, a reciprocatory feeder being represented. This latter may be of any suitable character, but in the form shown it consists of a plunger B operated by a screw shaft C provided at its end with a handle 0. At a. there is a feed 0 ening in the top wall of the guide A through which the material to be treated can be passed to the ore carrier. This is preferably sectional in form or construction, it being represented as formed of a series of pallets G each having a perforated bottom 9 and side walls g, the top and ends being left open. These pallets or carrier sections G are arranged to be placed end to end, and they together constitute a grate or ore carrier of indefinite length, according as many or few are employed. At some intermediate point along the guide A there is arranged a grate or perforated support D,

past which the carriers move, and separating them from an air box E that is connected by a pipe F with some suitable air described.

moving apparatus. The. sectional carrier seams gradually moved through or along the 'apparatus by the feeding mechanism already The plunger B may bear directly against, the pallet or section at the feed end of the ap aratus, although We prefer to interpose a b ock H between it and the end of the carrier.

On being advanced by the screw shaft C the plunger moves the ore mass and its carriers forward a, distance at least equal to the length -of one of the sections G, after which it is retracted and an other section put'in place to be filled with ore, when the forward movement again takes place. I indicates a shelf or su. port at the end of the ap aratus, upon Whic the ore, which is in the o'rm of a orous sintered cake or biscuit when it reac es thispoint,

passes, and where it may be brokenup and removed in any suitable manner, the sections of the carrier, as they are emptied,.being taken to the feedend of the apparatus for repeated use. I

Our process may now be described The fine ores or concentrates are arranged on the movable carrier'in a thin mass or layer, the

carrier being gradually fed forward as it is filled. A suflicient -mass of ore being provided the charge is ignited, -preferably at about the oint J. I ition maybe made by placing hurning coa s upon the top of the mass, or preferably by means of an oil or a gas flame arranged across the carrier so as to play upon the surface of the ore mass as it is moved past the line of ignition. After the charge has been ignited at the surface combustionis caused to extend gradually into the interior and through the mass, the air currents induced by the air movin" apparatus connected with the Wind-box E hastening the combustion, it being apparant that air will nass freely downward through that part of t e mass of ore that lies adjacentto the grate D covering the wind-box. The actionof the air currents employed to support combustion upon the ore mass has no uplifting or agitating effect on the fine particles of the ore, as would he the case should they move in an upward direction. Their tendency is rather to compact and hold in quiescence, relative to each other the particles at the top of the ore mass at the instant they are ignited and until they begin to form a layer of agglomerated or sintered material over the exposed surface of the mass. in our said earlier application we set forth the necessity of keeping the particles of ore in a quiescent state during certain stages of the treatment in order to insure a seems downward until the parts, resting upon the grate surface g of the carrier, have been reached and the entire mass thoroughly roasted and sintered.

In working our 1process we may mix about fifteen per cent. 0 crushed sinter from a previous operation with the concentrates or ores to be treated before charging the apparatus, and this we do for several reasons among which may be mentioned the following: first, to increase the porosity of. the charge, thereby decreasing the power required to force air through the mass; and second, to reduce the proportion of sulfur in the charge,

thereby enabling the process to be worked more ra idly and to prevent the formation of a too sible mass, keeping the ore mass granular and open for the passage of air until the process has been carried forward far enough for the sintering operation to take place. We do not, however, limit ourselves, in carrying out our process, to a mixing of sinter or any other substance with the ore, as the composition of the material being treatedwill to the skilled metallurgist indicate whether it should be mixed with other materials or not.

It will be understood that the form of carrier which we have illustrated, consisting of a perforated sectional grate upon which the material rests, while possessing many features of practical advantage, is but one type of carrier upon which the ore may be supported while subject to treatment according to our process. We do not, therefore, wish to be restricted in the use of our invention to the particular form of apparatus which we have herein shown for the purposes of illustration.

What we claim is:

1. The herein-described process of treating ores containing combustible elements to sinter them, which consists in moving a mass of the ore, firing it while being moved beginning. at the upper portions thereof, and subjecting the mass to a current of gas for supporting combustion, moving in a direction to cause combustion in the mass to pro ress in a downward direction, substantial y as set forth.

2 The herein-described process of treating ores containing combustible elements to sinter them, which consists in su porting the ore mass on a pervious screen, a vancing the screen and ore mass together, igniting or firing the ore mass, and passing ablast through the mass toward the screen, substantially as set forth.

3. The herein-described continuous process of treating ores containing combustible elements to sinter them, which consists in supporting the ore on a pervious screen or grate, advancing the screen and ore mass together, iCgmtin the ore from above at a point interme te etween the positions of feed then cooling the sintered mass, substantially as set forth.

5. The herein-described continuous process of treating ores containing combustible elements to sinter them, which consists in moving the ore between a position of feed and one of dischar e, ignitin the ore at a point intermediate etween t ese positions, passing ablast downward throu h the ore mass at points between its fee and discharge, and removing the sintered mass, substantially as set forth.

1 6. The herein-described continuous process of treating .ores containing combustible elements to sinter them, which consists in feeding the ore at one end of a roasting a paratus, removing the sintered product rom the other end, igniting the ore mass at a point intermediate between the said ends, supplying a blast to the upper side of the ore mass at points intermediate between the ends and causing the blast to pass through the mass of ore. v

7. The rocess of treating ores containing combustibqe constituents and sintering them, which consists, in arran 'ng the ore in a mass, igniting the combustib e constituents of the ore, advancing the ore-mass bodily after ignition, causing air or combustion-supporting gas to pass to the interior of the ore-body, and maintaining the particles of the said mass in quiescence relatively to each other while the mass is moving bodily, and agglomerating the said particles into a sintered mass, substantially as set forth.

8. The process of treating .metal bearing materials containing combustible constituents which consists 1n forming a mass of the material, moving the said mass bodily, igniting the combustible constituents of the mass, causing combustion of the said constitutents in the interior of the mass while it is moving, causing air or combustion-supporting gas to move throu h the said mass, and maintaining the partic es of the mass in advance of the re 'on of combustion in a condition of rest re atively to each other and to the mass while they are moving, substantially as set forth.

9. The rocess of sintering metal bearing ores or similar materials containing combustible constituents, consisting in forming material containin mass, maintaining combustion in the interior of the said successive parts of the mass, and maintaining the particles of the mass in ad- Vance of the region of combustion in a state' of rest in relation to each other and to the mass while they are moving, substantially as set forth.

10. The process of treating metal-bearing combustible elements, which consists in orming a mass thereof, supporting said mass so that it is movable bodily, igniting the combustible constituents of the mass at the top-thereof, moving said mass toand from a region of combustion, forming a layer or stratum of sinterat the top of the mass while it is in theregion of combustion, assing air or combustion-supporting gas t rough the said sinter stratum, causing the area of combustion to move downward through the mass in the direction of travel of the airand gas, sintering the lower stratum of the mass, and moving the mass bodily from the region of combustion, substantially as set forth.

11. The. process of treating metal-bearing material containing combustible ingredients, which consists in forming a mass thereof,

supporting said mass so that it is movable bodily, igniting the mass, forming a stratum of sinter in the region of the initial ignition, moving the mass bodily to a region of conibustion, causing combustion-supporting gas to enter the interior of the mass while in said region of combustion, maintaining the particles of the body of the mass which are in advance of the region of ignition in substantially fixed relation to each other and to the mass, whereby the particles while in the region of combustion are held against agitation or disturbance, and moving the mass bodily after combustion away from the region of combustion, substantially as set forth.

12. The process of treating metal-bearing material containing combustible constituents,. which consists in forming a mass or layer thereof, supporting the said mass so that it is bodily movable, igniting the mass,

moving. the said mass to a region of combustion and sintering, forming a stratum of sinter in the region of the initial ignition, causing combustion supporting gas to enter the interior of the mass, maintaining the particles of the body of the mass which are in advance "of the region of ignition in substantially fixed relation to each other and to the mass, whereby the particles while in the region of combustion and sintering are held against agitation or disturbance, the combustion traveling through the mass in the same direction as the combustion-supporting gas, and moving the mass bodily away from the region of combustion and sintering, sub,- stantially as set forth. v

13. The process of treating metal-bearing ores in relatively fine condition containing combustible elements which consists in forming a mass of the ore, supporting the said mass so that the successive parts thereof are bodily movable, igniting the combustible ingredients of the ore, moving the mass as described, to have the successive parts thereof reach a region of combustion, causing combustion-supporting gas to pass to the interior of the successive parts of the mass, raising the temperature of the interior of the mass by internal combustion to the point of sinterforming, restraining from agitation or movement the parts of ore on the side where the gases or products of combustion escape and moving the parts of the mass successively away from the region of-combustion and sintering, substantially as set forth.

14. The process of treating metal-bearing ores in relative fine condition and containing combustible constituents, which consists in forming a thin bed or mass of the ore, igniting the combustible constituents of the ore, advancing the ore mass bodily after ignition, causing combustion-supporting gas to pass through the bed or mass of ore, maintaining the particles of the ore in quiescence relative to each other while the mass is moving bodily, and removing the sintered ore mass after it has passed beyond the region of combustion, substantially as set forth.

15. The process of treating ores containing combustible constituents and sintering them, which consists in arranging the ore in a mass upon a movable pervious screen or grate, igniting the combustible constituents of the ore, advancing the grate and ore mass together bodily, causing air to pass through a the ore mass and grate to support combustion within the ore mass, and maintaining the particles of the said mass in quiescence relative to each other while the mass is moving bodily.

16. The herein-described process of treating fine ores containing combustible constituents to sinter the same, which consists in arranging the ore in a mass, moving the mass bodily to bring it into the path of the air current, roasting and sintering the ore by internal combustion while in such air path, moving the mass bodily to carry it out of the air path, and removing the sintered roduct while out of the air path, substantial y as set forth.

17. The herein-describedprocess of treating metallic ores containing combustible constituents, which consists in arranging the ore in'a mass or bed having an exposed. surface, igniting the "exposed surface of the ore, causing air to pass from the said exposed surface to the interior of and through the ore body to insure internal Combustion in the ore mass for sintering it, moving the ore bodily as a mass to positions for igniting and for combustion to form the sinter, and finally moving the mass to position for removing the sinter.

In testimony whereof we affix our signatures, 1n presence of two witnesses.

ARTHUR S. DWIGHT. RICHARD L. LLOYD.

Witnesses:

FEDERI O RAMOS BARRESO, WM. LEWIN. 

